Normally, an automobile crank case is provided with a drain plug on its underside. When it becomes necessary to change the oil, a garage mechanic will simply remove the oil plug from underneath the crank case and permit the oil to drain into a funnel or similar structure or sometimes simply let it spill on the garage floor. After drainage is complete, the garage mechanic will then replace the drain plug and new oil is then poured into the crank case.
The foregoing operation is time consuming and messy. As a consequence, there have been a number of proposals for facilitating the draining of oil from an engine crank case.
One such proposal involves placing a wrench socket within a funnel so that when the drain plug is unthreaded, the funnel is in proper position to catch oil as it drains from the crank case. In other instances, an actual valve has been designed and proposed for substitution for the normal drain plug so that rather than remove the drain plug, it is only necessary for an operator to open the valve. In this latter arrangement, it is still necessary to provide a funnel or some other means properly disposed to catch the oil after the valve has been opened.
Thus, while the above proposed substitution of a drain valve for a drain plug will eliminate the necessity for tools provided that the valve can be manually opened and closed, there still exists the problem of oil spillage and soiling of the operator's hands in operating the valve.